Audio amplifiers are widely employed for a variety of applications. For example, audio amplifiers are commonly employed in music devices, computers, televisions, telephones, and/or the like. Listeners of such devices generally prefer high quality audio outputs. As such, characteristics such as frequency response, total harmonic distortion (THD), signal to noise ratio (SNR), perceived audio quality (e.g., perceptual evaluation of audio quality (PEAQ), mean opinion score (MOS), etc.), and/or the like may be employed to characterize an audio amplifier.
One type of undesirable noise includes “pops” or “clicks” that may be generated, for example, by initial switching of an audio amplifier's output, or other switching circuit (e.g., when unmuting the output, during start-up, etc.). In the context of an audio system, this type of switching noise may distract a listener, especially since this initial switching follows periods of relative silence (e.g., start of musical tracks, when unmuting, following musical lulls, start-up, or periods of silence, or following periods for which an audio output is below a threshold, etc.).
Certain audio amplifier topologies (e.g., class D audio amplifiers, amplifiers with complementary switch circuits, etc.) may be more likely to produce noticeable pops or clicks than others. As one example, non-linear switching waveforms in class D amplifiers may generate transients at the speaker that cause pops or clicks. Likewise, amplifiers with complementary output stages may also provide relatively larger transients at the speaker due to the increased output range typically associated with complementary output stages.